Process of and apparatus for degasifying liquids and washing gases



R. BECKER 2,310,829 PROCESS OF AND APPARATUS FOR DEGASIFYING LIQUIDS ANDWASHING GASES;

Filed Aug. 6. 1940 INVENTOR RUDOLF BECKER RNEY rectification.degasification of liquids by counter-currentlying to the inventionthereto,

atented Feb. 9, 1943 H Eff A maze PROCESS OF AND A a LlQS AND TUS FORDEGAS- WASHING GASES lltudoli Becker, Munich-Solln, Germany: vested inperty Custodian In Germany August 17, 1939 5 Claims. (01. 261-413) to aprocess of and apfor washing This invention relates paratus fordegasifying liquids and gases.

Gas washing as well as the degasification of liquids is generallycarried out by permitting the liquid to flow over individual trays in awash column against the flow of the'gas, whereby gas and liquid arebrought into intimate contact and attain a state of substantialequilibrium with one another. When iacedby this problem, which is verysimilar to rectification, it appears obviously advisable to utilizethose apparatus arrangements which have been proven successful in thefield of rectification.

In so far as this relates to columns with simple insets or fillerbodies, it is possible to utilize such apparatus as washers ordegasification towers without major construction alterations.

However, in attempting to utilize particularly eficient rectificationtrays, such as circular or annulartrays, for washing gases with liquids,for example, dimculties have been encountered. chiefly due to the factthat in gas washing appreciably more liquid is employed compared to thegas volume throughput than is employed in The same conditions exist inthe conducted gas.

If, however, a circular tray column of the known type is operated with alarge volume of liquid, the pressure drop especially through theindividualtrays rises very appreciably because the high liquidthroughput results in very large liquid cross-sections andcorrespondingly high liquid levels. Such high liquid levels howevercannot be reduced by increasing the velocity of flow because, due to thecontinuous changes in direction undergone by the liquid, the centrifugalforce an unequal distribution of the liquid over the Due to the largepressure dr "through the individual trays, it is naturally impossible toconstruct wash-columns of this type with a greater number of trays.However, according to the invention, it is still possible to apply togas washing the circular tray principle used with great success inrectification, namely. the maintenance of a concentration-gradientwithin each individual tray. It. has been found that the abovementioneddifliculties can be eliminated by interchanging the paths followed bythe liquid or gas in the known circular tray. Accordthe preferablyfinely divided liquid flows vertically downwards through perforations ofthe trays while the gas is conducted in cross-current thereto in acircular path over the individual'trays.

The formation of a concentration-gradient within each tray, whichimproves the efficiency of the column in the'known manner, is favored bythe fact that the flow of the gas over the individual trays is effectedalways in the same way for example, always clockwise or alwayscounter-clockwise in a substantially helical path.

Thus a principle object of the invention is to provide a method ficientgas and liquid contact providing the advantages of annular rectifyingtrays for gas washing and for degasification of liquids. The above. andother objects of. the invention will become evident fromthe followingdescription in connection with the accompanying drawing which is aperspective view of a portion of an at too high a velocity would causeexemplary washing tower with a part broken away to illustrate theinternal arrangement.

An operating example of the process accord- 7 ing to the invention willbe described with the aid of the illustration. The drawing shows asection including -four trays of the newly developed wash column with aportion of the shell 8 broken away. IIhe trays consist of perforatedplates it provided with narrow holes or slits Ii, said plates beinginserted between the outer cylindrical casing 8 and aninner axiallydisposed displacement or filler body 9 and supporting a radialseparating wall or partition M which entirely closes off each circularchamber at a point adjacent a tray to the next higher tray. Each wall itex: tends through and above the next higher tray sufficiently to'form abarrieror dami2 so that the liquid is dammed up on the tray and forcedto flow down through the holes or slits H in *the tray. The separatingwalls M are so staggered on consecutive trays it that gas can flowthrough the remaining sector or opening 15 in the tray between walls Mand barriers i2. The

- dammed up height of liquid on each periorated plate is therebydependent upon the volume of liquid throughput. Nevertheless, it ispossible for the liquid throughput to fluctuate extensively withoutdisturbing the functioning of the column due to the fact that the volumeflowing downward through the holes H of each per forated plate increaseswith the growing hydrostatic pressure of the liquid volume on the tray.The liquid trickles through II in the perforated I plate in, a finelysdivided state to the next tray,

whereby it passes through and apparatus for effecting efgas passage i5through the the holes or slits Y gas is limited by the partition id insuch a way that the gas is guided in a circle and in a clockwisedirection over each perforated tray and after flowing around the chamberabove one tray, it enters into the next higher chamber through theopening l5 cut in the next higher perforated plate and flows throughsaid higher chamber in the same circular direction. By conducting thegas and liquid in cross-section fashion, and

causing the liquid to pass through successive revolutions of the gas, anintimate contact between liquid and vapor is attained.

According to a further thought of the invention, a number of radialpartitions may be provided on the perforatedplates, the height of suchpartitions being so measured that they prevent an intermixing of theliquid on the perforated plate in a peripheral direction, but do notlimit the flow of the gas. Such partitions confine the -ing out gaswashing under pressure, whereby appreciable savings in material arepossible due dimensions of the column because of the much greater liquidand gas contact emciency. A further advantage of the new processconsists therein that the number of wash trays required is very low;furthermore, the pressure drop between the ends of the column isincomparably smaller than with the heretofore known forms of constructioWhat is claimed is:v

1. A process for degasifying a liquid or for washing gas with a liquidwhich comprises feed; ing the liquid into the upper portion of a washingcolumn conducting the gas upwardly through said column in a successionof substantially annular paths and always in the same direction ofrevolution: causing all the liquid fed to the column to flow verticallydownward through the column across said succession o1 paths and insubstantially parallel finely divided streams whereby the movement ofall liquid in the column is transversely across the paths'of gas flow;and'eflecting substantially uniform distribution of said liquid streamsthroughout each of said substantially annular paths.

liquid and a ing; an inner axial member; a series of annular perforatedtrays forming annular chambers with said outer casing andvsaid member;apartition extending across each annular chamber and Joining consecutivetrays: said partitions being disposed in staggered relation to eachother; each tray being provided with a gas passage opening therethrough,each such gas passage opening being adjacent to and on the samecorresponding side of the respective partition across the chamber abovethe tray having such opening; and at least one darn extending acrosseach annular tray for maintaining a desired maximum depth of liquid oneach tray; 7 q

3. Apparatus as claimed in claim 2 in which each of said perforatedannular trays is provided with a series of peripherally spaced radialbarrier walls of a height sunicient to prevent substantial intermixingof the liquid on the tray but of insumcient height to substantiallyinterfere with the flow of the gas.

4. Apparatus for effecting contact between a gas which comprises anouter casing; an inner axial'member; a series of annular perforatedtrays forming annular chambers with said outer casing and said innermember; a partition extending across each and joining consecutive trays;each of said partitions being offset with respect to each next lowerpartition by approximately the same discolumn, each of said partitionsextending above the tray next above it for a distance suflicient to forma dam, each of said trays having a gas passagetherethrough locatedbetween the dam formed by the next lower partition and the partitionnext above said tray, and the height of each dam being sufiicient toretain liquid on the corresponding tray to a desired maximum height andcause such liquid to flow downwardly through the perforations in suchtray.

5. Apparatus for effecting contact between a liquid and a gas whichcomprises a washing col- 2. Apparatus for effecting contact between aumn having therein contact means including a series 01' annularperforated trays, constructed and arranged for conducting a gas upwardlythrough said column in a toconfine the flow of all

